Puerto Ricans bear a great burden from diabetes. The incidence of insulin deficient diabetes (IDDM) is the highest reported in the US for both the island and mainland populations. The prevalence rate of insulin resistant diabetes (NIDDM) is 2-fold higher than rates of non Hispanic Caucasians; 1 of 4 Puerto Ricans over the age 40 has NIDDM. Like the etiology of diabetes, the etiology of diabetic susceptibility is unknown. Under the WHO DiaMond genetic project, we have shown that HLA Class II DR and DQ genes are clearly susceptibility markers to childhood IDDM in Puerto Ricans. However, these alleles occur with similar frequencies in all reported ethnically mixed Western hemisphere populations and do not account for the increased incidence of diabetes in PR. We now propose that genetic and cultural factors interact in Puerto Ricans to induce either a novel type of diabetes, and/or onset at an earlier age, leading to excessive disease rates. To test these hypotheses, we will expand the IDDM registry to include a sub-registry of non-insulin requiring childhood cases of diabetes to ascertain the following epidemiology of the disease: age of onset, sex distribution, seasonal and geographical variation of the disease. Utilizing our network of diabetes registration, we will begin immunological studies of newly diagnosed diabetics, both IDDM, NIDDM and controls to determine the autoimmune nature of PR diabetes. To ascertain if there are genetic similarities between insulin and non-insulin dependent children, we will type the HLA region of patients with childhood onset NIDDM and compare it with our data base of IDDM and controls. Additionally, as part of our participation in WHO DiaComp project, we will continue to monitor complication rates of IDDM patients and to confirm patient-reported complications of the first phases of this project. These studies will better enable us to characterize childhood diabetes in Puerto Ricans. Because of the therapeutic differences in treatment of insulin deficient and insulin resistant diabetes, these data will help to determine if present standards of childhood diabetic care should be modified for the Puerto Rican population.